The \"excessive\" use of vocational equivalents is \"inflating\" the results of England\'s academy schools, analysis of league table data suggests. Thousands of the qualifications which are deemed easier than GCSEs were devalued by the government this week.But analysis by school improvement expert Dr Terry Wrigley shows 68% of academies rely more heavily on them than the average state school.The government said the gap diminished the longer sponsor academies were open.But Dr Wrigley, editor of the international journal Improving Schools and visiting professor at Leeds Metropolitan University, described many academies\' use of equivalents as \"excessive\".\"This seriously inflates the attainment figures for academies, compared with all schools nationally, creating a false impression that they are successful,\" he said. This week Schools Minister Nick Gibb reduced the number of so-called equivalents that will count for league table purposes from 2014 from more than 3,000 to 70. \'Policy clash\' Vocational courses - in subjects like catering, travel and tourism, life skills and IT - currently count for up to four GCSEs.And there have long been claims that some schools get borderline pupils through the five good GCSEs including English and maths benchmark by focusing on those two subjects plus an equivalent worth four GCSEs.It is particularly important because this is the measure used by the government to measures school performance.Dr Wrigley said: \"We have got Michael Gove pushing massively for academies and now even primary schools are being pushed into becoming academies. \"At the same time as scrapping these equivalents for league table purposes, he is relying on these results as part of his argument that academies are better.\"He can\'t hold on to both policies now. He has gone a lot further than the previous government in pushing schools into academy status.\"Dr Wrigley looked at the performance of England\'s 269 academies with results in the 2011 school league tables against the average performance of state secondary schools. \'Rigid definition\'In all maintained schools, 59.1% of pupils got five good GCSEs including English and maths, including equivalents.But when equivalents were not included, it dropped to 53.2% - a gap of nearly six percentage points. For academies, 50.1% got the benchmark if equivalents were included in the figures, but without equivalents it dropped to 38.3%. This is nearly the double the gap for all state schools.He found that of the 269 academies, some two-thirds (183) had gaps of more than six percentage points.And more than half (141) academies had gaps of 10 percentage points or more.In one academy, 70% of pupils got five good GCSEs, but this reduced to zero when equivalents were discounted.Dr Wrigley also looked at how disadvantaged pupils performed in academies and in maintained schools. He says: \"Nationally, Nick Gibb complains that only 33.9% of disadvantaged pupils achieved five A* to C grade GCSEs including English and maths, compared to the national average of 58.2% in maintained schools.\"Around half of academies did worse than this, and many would have fallen below the proportion if they hadn\'t made extensive use of \'equivalent\' qualifications that the government is about to abolish as suspect.\"A Department for Education spokesman said: \"The vast majority of academies in these statistics are sponsored academies transforming previously underperforming schools and serving some of the most deprived communities, and so they initially concentrate on improving the basics.\"However, if you look at the major sponsors, there is a clear trend that once academies have been opened and established they move to more academic subjects.\" He added that academies\' results, including in the core subjects of English and maths, were improving faster than the national average. The general secretary of the National Union of Teachers, Christine Blower, said: \"What the results reveal is that changing the structure of a school will not change the context it works in or its ability to meet the needs of the pupils within it.\"As with other schools, academies have inevitably had to play the league tables game, so it has come as no surprise to see that many do not meet Michael Gove\'s own rigid definition of a successful school.\"Instead of the education secretary\'s obsession with turning all schools, including primaries, into academies, he needs to sit down with the profession and engage in a serous dialogue about what schools need to provide the best possible education for all children.\"